Second Department of Cardiology, University of Athens, Attikon University Hospital, Athens, Greece.
Eur Heart J. 2013 Jul;34(26):1964-71. doi: 10.1093/eurheartj/eht109. Epub 2013 May 3.
Patients who have experienced a myocardial infarction (MI) are at increased risk of sudden cardiac death (SCD). With the advent of implantable cardioverter-defibrillators (ICDs), accurate risk stratification has become very relevant. Numerous investigations have proven that a reduced left ventricular ejection fraction (LVEF) significantly increases the SCD risk. Furthermore, ICD implantation in patients with reduced LVEF confers significant survival benefit. As a result, LVEF is the cornerstone of current decision making for prophylactic ICD implantation after MI. However, LVEF as standalone risk stratifier has major limitations: (i) the majority of SCD cases occur in patients with preserved or moderately reduced LVEF, (ii) only relatively few patients with reduced LVEF will benefit from an ICD (most will never experience a threatening arrhythmic event, others have a high risk for non-sudden death), (iii) a reduced LVEF is a risk factor for both sudden and non-sudden death. Several other non-invasive and invasive risk stratifiers, such as ventricular ectopy, QRS duration, signal-averaged electrocardiogram, microvolt T-wave alternans, markers of autonomic tone as well as programmed ventricular stimulation, have been evaluated. However, none of these techniques has unequivocally demonstrated the efficacy when applied alone or in combination with LVEF. Apart from their limited sensitivity, most of them are risk factors for both sudden and non-sudden death. Considering the multiple mechanisms involved in SCD, it seems unlikely that a single test will prove adequate for all patients. A combination of clinical characteristics with selected stratification tools may significantly improve risk stratification in the future.
经历心肌梗死（MI）的患者发生心源性猝死（SCD）的风险增加。随着植入式心脏复律除颤器（ICD）的出现，准确的风险分层变得非常重要。大量研究证明，左心室射血分数（LVEF）降低会显著增加 SCD 风险。此外，在 LVEF 降低的患者中植入 ICD 可显著提高生存率。因此，LVEF 是当前 MI 后预防性 ICD 植入决策的基石。然而，LVEF 作为独立的风险分层器存在重大局限性：（i）大多数 SCD 病例发生在 LVEF 正常或中度降低的患者中，（ii）只有相对较少的 LVEF 降低患者会从 ICD 中受益（大多数患者永远不会经历威胁性心律失常事件，其他患者发生非心源性猝死的风险较高），（iii）LVEF 降低是心源性猝死和非心源性猝死的风险因素。已经评估了几种其他非侵入性和侵入性风险分层器，如室性心律失常、QRS 持续时间、信号平均心电图、微伏 T 波交替、自主神经张力标志物以及程控心室刺激。然而，这些技术中没有一种能够单独或与 LVEF 联合使用时明确证明其疗效。除了敏感性有限之外，它们大多数都是心源性猝死和非心源性猝死的风险因素。鉴于 SCD 涉及多种机制，似乎不太可能有一种单一的测试方法适用于所有患者。将临床特征与选定的分层工具相结合可能会显著提高未来的风险分层。
